<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    for(b = 0;b<6;b++){
        for(a = 0;a<b;a++){
            document.write("*");
        }
        document.write("<br>");
    }
</script>
</body>
</html>